Allmendinger said in an interview with ESPN that he took Adderall a couple of days before the race at Kentucky Speedway on June 30 because he was tired. He does not have ADHD or a prescription for the drug.

He says a friend gave him the pill and said it was a workout supplement that would give him energy.

Two days later he was randomly tested at the racetrack.

Allmendinger told ESPN that he wasn’t informed what drug triggered the positive test _ only that it was an amphetamine _ until after a B sample was tested July 24.

Allmendinger, who said he had never taken the drug before, is now going through NASCAR’s Road to Recovery program. He said he hopes to complete the program by the end of August.

Spokesman David Higdon said NASCAR is unaware of the specific substance Allmendinger took. Higdon said testing won’t reveal the brand of a substance.